KR101678688B1 - Illumination system and method for recycling light to increase the brightness of the light source - Google Patents

Abstract

An illumination system for increasing the brightness of a light source of the present invention includes an optical recycling apparatus 200 coupled to a light source 100, preferably a light emitting diode (LED), for spatially and / or angularly recycling light do. The optical recycling apparatus 200 may use a reflector or mirror 400 to spatially recycle a portion of the light emitted by the LED to the light source 100 and / And increases the brightness of the output of the light source 100. [

Light source, luminance, lighting device, light source, optical recycling device, light pipe

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination system and method for recycling light to increase the brightness of a light source,

The present invention relates to a system and method for increasing the brightness of an illumination system, and more particularly to an illumination system and method for recycling light emitted from a light source to increase the brightness of the light source.

Light sources are used in all types of lighting applications. Typical light sources include, but are not limited to, arc lamps, halogens, fluorescent devices, microwave lamps, and light emitting diodes (LEDs). Many applications require an illumination system with a high level of brightness at a small effective light emitting area. In the past, it was possible to achieve such a high level of brightness by adding more light sources. However, this is not technically impossible if there is a space limitation in incorporating the light source, and it may not be economically suitable because it is expensive to incorporate and use multiple light sources.

For example, microdisplay based television (MDTV) has the possibility of providing a large-sized screen at low cost. Conventional MDTVs are typically illuminated by arc lamps. The light source may be the brightest at the lowest cost, but is less desirable due to the requirement to divide the white light into three colors and the short life span. As LED technology advances, the use of LEDs as a light source in MDTV must be considered to achieve other benefits such as long lifetime characteristics of LEDs and instant ON. However, current LEDs are not bright enough for low-cost applications with small imaging panels or with larger screens. The LED recycling concept was used in U.S. Patent No. 6,869,206 to Zimmerman et al. To enhance the brightness of the light source. However, the Zimmerman et al patent discloses housing LEDs in a light reflective cavity with one light output opening. U.S. Patent No. 6,144,536 to Zimmerman et al. Discloses a fluorescent lamp having a glass envelope with a phorsphor coating that accommodates a gas-filled hollow interior. Some of the light generated by the glare coating is recycled back to the glaze coating. The present invention provides a recycling apparatus that can be coupled to one or more LEDs to increase the usable brightness of the LED by efficient recycling so that a smaller panel can be used or a larger screen can be illuminated with sufficient brightness The purpose.

For example, LEDs are one type of light source used in various lighting applications, such as general lighting, architectural lighting, and more recently, projection television. For example, when used in a projection television, the LED must emit light in a small effective light-emitting area at a high luminance level to provide the necessary high light output on the television screen. In particular, LEDs must provide strong and bright light when computed in a lumen with small and solid angles within a small light emitting region, which is useful for projection televisions. Unfortunately, currently commercialized LEDs are not bright enough to be useful for lighting consumers' increasingly preferred large projection television screens.

Therefore, there is a need for a method and system for increasing the brightness of an LED to provide a lighting system that meets the needs of current and future applications at an affordable price.

It is therefore an object of the present invention to provide a lighting system that solves the above-mentioned problems of the prior art.

It is another object of the present invention to provide an illumination system comprising a recycling device for recycling a portion of the light emitted by the light source to increase the brightness of the output light.

It is another object of the present invention to provide a lighting system including a spatial recycling apparatus for recycling a part of light emitted by a light source to the light source in order to increase the brightness of the output light.

It is still another object of the present invention to provide an illumination system including an angle recycling apparatus that transmits light at a small angle to recycle light at a high angle to increase the brightness of output light.

It is yet another object of the present invention to provide an illumination system including a space and angle recycling device for recycling a portion of light emitted by a light source to increase the brightness of the output light.

It is a further object of the present invention to provide a lighting system as described above which further comprises a polarizer for reflecting and recycling light having undesired polarization, thereby enhancing the recycling effect of the recycling device.

The present invention relates to an illumination system for recycling light to increase the brightness of a light source, which allows the illumination system to provide a higher output of light at a reasonable price. According to an exemplary embodiment of the present invention, an illumination system for recycling light to increase brightness comprises a space recycling device. The space recycling apparatus includes a light pipe coupled to a light source, preferably an LED chip mounted on the substrate. The space recycling apparatus recycles light by coating a part of the output end of the light pipe with a reflecting medium or by coating the light from the light source to be reflected back to the light source through the light pipe by the reflecting medium. The light source re-emits the light reflected by the light pipe, thereby increasing the brightness of the light output from the illumination system.

According to an exemplary embodiment of the present invention, an illumination system for recycling light to increase brightness comprises an angle recycling device. The angle recycling apparatus includes a tapered light pipe coupled to a light source, preferably an LED chip mounted on the substrate. Preferably, the tapered light pipe is a reduced tapered light pipe in which the light pipe is tapered to a small cross-sectional dimension of the output end at a large cross-sectional dimension of the input end. The angle recycling apparatus transmits a small angle of light and reflects a large angle of light back to the light source. The light source re-emits the light reflected by the different angular distribution, thereby increasing the brightness of the output light.

According to an exemplary embodiment of the present invention, an angle recycling apparatus comprises a reduced tapered light pipe coupled to a light source, preferably an LED chip mounted on a substrate, and an increment coupled to the output end of the reduced tapered light pipe, Tapered light pipe. The reduced tapered light pipe tapers from the small cross-sectional dimension of the input end to the large cross-sectional dimension of the output end. The angle recycling apparatus transmits a small angle of light, reflects a large angle of light back to the light source, and increases the brightness of the output light.

According to an exemplary embodiment of the present invention, an angle recycling apparatus includes a lens system coupled to a light source, preferably an LED chip mounted on a substrate. The lens system includes a lens surface or lens in the center surrounded by a concave reflector or reflective surface. Alternatively, the reflector may be a dual parabolic reflector that reflects a high angle of light twice before being focused again on the LED chip. The reflector and reflective surface retroreflect a high angle of light back to the LED chip for recycling and the lens or lens surface is coupled to the light output with a small angle of light to increase the brightness of the output light.

According to an exemplary embodiment of the present invention, an optical recycling apparatus for increasing the brightness of a light source includes a transmission medium that transmits a plurality of light beams from a light source. The transmission medium has an output end and an input end coupled to the light source. The mirror or reflector reflects some of the plurality of light rays back to the light source through the input end of the transmission medium so that some of the plurality of light rays are re-emitted by the light source to reuse some of the plurality of light rays, To increase the brightness of the output of the light source.

According to an exemplary embodiment of the present invention, a method for increasing the brightness of an illumination system includes providing a light pipe further comprising a light source, a reflective medium disposed at an output end, the light pipe including an input end and an output end, The method comprising the steps of generating a light beam by a light source, placing a light pipe such that the input end is substantially in proximity to the light source, reflecting part of the light beam back to the light pipe by a reflective medium, Coupling light rays reflected from the output end of the light pipe and outputting the reflected light from the output end of the light pipe to recycle light to increase the brightness of the illumination system.

According to an exemplary embodiment of the present invention, a method for increasing the brightness of an illumination system includes a light source and a tapered light pipe having an input end and an output end and tapering from a large cross sectional dimension of the input end to a small cross sectional dimension of the output end. Providing a tapered light pipe with the input end generally proximate to the light source; receiving a light beam at the input end; and providing a portion of the light beam at a wide angle Reflecting off the tapered light pipe to reduce each dimension, and outputting small angular light from the output end.

According to an exemplary embodiment of the present invention, a method for increasing the brightness of a light source includes coupling an optical recycling device to a light source to receive a plurality of light beams from the light source, And re-emitting some of the plurality of light beams to the optical recycling apparatus by the light source, thereby increasing the luminance of the output of the light source.

Various other objects, advantages and features of the present invention will become readily apparent from the detailed description and the novel features are pointed out with particularity in the appended claims.

The following detailed description, which is provided by way of example and which by no means restrictive the present invention, will be better understood in connection with the accompanying drawings, wherein like components or configurations are represented by like reference numerals in various configurations.

1 is a cross-sectional view of an LED chip mounted on a substrate,

Figure 2 shows the LED of Figure 1 coupled to a light pipe,

3 is a cross-sectional view of an illumination system according to an exemplary embodiment of the present invention, showing a reflector or mirror covering a portion of the output end of the light pipe,

Figure 4 illustrates the illumination system of Figure 3 further comprising a polarizer covering a portion of the output end of the light pipe not covered by the reflector in accordance with an exemplary embodiment of the present invention,

5 is a cross-sectional view of an illumination system according to an exemplary embodiment of the present invention, showing a reflector about the periphery of the output end of the tapered light pipe,

Figure 6 is a cross-sectional view of a reduced tapered light pipe recycling light in accordance with an exemplary embodiment of the present invention,

7 is a cross-sectional view of an illumination system including a reduced tapered light pipe of FIG. 7 according to an exemplary embodiment of the present invention having a tapered light pipe,

8 is a cross-sectional view of an illumination system including two tapered light pipes coupled together in accordance with an exemplary embodiment of the present invention,

Figures 9a and 9b illustrate two LEDs mounted on a substrate, with a reflective coating disposed on a substrate between LEDs and each coupled to a straight or tapered light pipe, according to an exemplary embodiment of the present invention Sectional view of an illumination system including an LED,

10A and 10B are cross-sectional views of two LEDs according to an exemplary embodiment of the present invention, which are mounted on a substrate and have a straight or tapered light pipe with a reflective coating disposed on the input end of the light pipe between the LEDs Sectional view of an illumination system including a coupled LED,

11A is a perspective view of a light source module coupled to each of the LEDs at the input end, each coupled to an identical linear light pipe with a reflector spatially reusing light to cover a portion of the output end at the output end, in accordance with an exemplary embodiment of the present invention Sectional view of an illumination system comprising two tapered light pipes,

11B shows two tapered light pipes, each coupled to an LED at the input end and coupled to the same reduced tapered light pipe, each of which is optically recycled at the output end, according to an exemplary embodiment of the present invention / RTI > is a cross-

Figure 12 is a cross-sectional view of the illumination system of Figure 11A further comprising a reflective polarizer covering the output end of the linear light pipe in accordance with an exemplary embodiment of the present invention,

13A-13D are cross-sectional views of an illumination system including a color beam combiner coupled to a straight or tapered light pipe to couple the outputs of three LED chips in accordance with an exemplary embodiment of the present invention,

14A and 14B are cross-sectional views of a lighting system including a straight or tapered light pipe coupled to an LED on a substrate and a mounting frame for mounting a glass plate in accordance with an exemplary embodiment of the present invention,

Figs. 15A and 15B are the illumination systems of Figs. 14A and 14B including two LED chips,

16 is a perspective view of a solid optical system having two concave reflective surfaces for retroreflecting light rays at a large angle to recirculate light angularly according to an exemplary embodiment of the present invention and a lens surface for coupling light rays at a small angle; Sectional view of an illumination system including components,

17 is a cross-sectional view of an illumination system including a concave reflector for retroreflecting a large angle of light to recirculate light angularly according to an exemplary embodiment of the present invention and a lens for coupling a small angle of light ,

Figure 18 is a cross-sectional view of the illumination system of Figures 16 and 17 for angularly recycling light using a dual parabolic reflector or reflective surface according to an exemplary embodiment of the present invention,

19 is a sectional view of an LED lighting system incorporating an optical recycling apparatus according to an exemplary embodiment of the present invention,

20 is a cross-sectional view of an LED lighting system having an LED chip with a coalescing optical device incorporating an optical recycling apparatus according to an exemplary embodiment of the present invention,

21 is a cross-sectional view of an LED projection system incorporating an optical recycling apparatus according to an exemplary embodiment of the present invention,

22 is a cross-sectional view of an optical fiber system incorporating an optical recycling apparatus according to an exemplary embodiment of the present invention,

Figure 23 is a cross-sectional view of the LED projection system of Figure 21 or the optical fiber system of Figure 22 with an LED chip with coalesced optics,

Figure 24 shows a calculated brightness enhancement curve for various LED reflectivities according to an exemplary embodiment of the present invention,

Figure 25 shows an experimental brightness enhancement curve for various LED reflectivities according to an exemplary embodiment of the present invention,

Figure 26 shows a calculated luminance enhancement curve in which an LED is closely located in the vicinity of a light pipe in accordance with an exemplary embodiment of the present invention.

Referring to the drawings, an illustrative embodiment of the present invention is described. These embodiments illustrate the principles of the invention and are not to be construed as limiting the scope of the invention.

According to an exemplary embodiment of the present invention, an illumination system 1000 for recycling light to increase the brightness of a light source, as shown in FIGS. 3 to 5 and 7 to 18, includes a light source 100, Device 200 as shown in FIG. As shown in FIG. 1, the light source 100 is mounted on a substrate 140. However, the substrate 140 is preferably not limited to a heat sink 140 that absorbs and disperses heat emitted from the light source 100. The light source 100 is preferably a light emitting diode ("LED"). Alternatively, the LED light source 100 may be mounted on the substrate 140 as a bare chip, with the chip having a protective coating, or with a lens or collimating lens. The chip size may be less than 1 mm < 2 > or may be of a size that is technically feasible. The commercial chip may have dimensions of about 3 mm to 5 mm. The dimensions of these chips are increasing over time as the skill becomes more skilled. The lens mounted on the LED chip 100 may be spherical or may be made of any shape chip to obtain maximum coupling, such as an aspherical surface, or a combination of a molded lens for transmission or a surface formed for reflection Lt; / RTI > Although the illumination system of the present invention has been described using an LED as the light source 100, the light source 100 can be, for example, an arc lamp, a halogen lamp, a surface emitting device (SEDs), a fluorescent device, a microwave lamp, But may be any light source including but not limited to other known light sources. According to one embodiment of the present invention, the system may include a plurality of light sources 100 mounted on a single substrate 140, as shown in Figures 9A-13D, 15A and 15B. According to one aspect of the invention, each light source 100 may be mounted on a separate substrate 140 as shown in FIGS. 11A-12.

According to an exemplary embodiment of the present invention, the optical device 200 may be a spatial and / or angular recycling device that is in optical communication with the light source 100. As disclosed herein, the space or angle recycling apparatus 200 generally includes a straight or tapered light pipe 300. 2, the output of the light source or LED 100 is coupled to the light pipe 300 to provide a uniform intensity profile of the light at the output end 320 of the light pipe 300. Light within the light pipe 300 is guided to the output end 320 through total intervention. The output of the LED 100 is captured by the light pipe 300 and transmitted to the output end 320 of the light pipe 300. The light pipe 300 may be rectangular, hexagonal, or triangular. The shape of the light pipe 300 preferably matches the shape of the light source or LED 100 for high coupling efficiency. In an ideal case, the output of the LED 100 is completely captured by the light pipe 300. The output luminance at the output end 320 of the light pipe 300 will be approximately the same as the output luminance of the LED 100 if the cross sectional dimension of the light pipe 300 coincides with the LED 100. [ However, in a commercial application, slight coupling loss between the LED 100 and the light pipe 300 and transmission loss in the light pipe 300 are expected.

According to an exemplary embodiment of the present invention, as shown in Figs. 3 to 5, 9A, 10A, 11A, 12, 13A, 14A and 15A, the spatial optical recycling apparatus 200 Reflector system 400 coupled to a light pipe 300 and to an output end 320 of the light pipe 300. The input end 310 of the light pipe 300 is optically communicated or coupled to the light source 100 and the output end 320 is coupled to the reflective medium 400. Optical communication can be achieved by placing the light pipe 300 near the light source 100 so that the input end 310 of the light pipe 300 condenses the light emitted from the light source 100. [ Alternatively, the input end 310 of the light pipe 300 may be attached to or adhered to the light source 100 using an epoxy or any other heat resistant transparent connecting material. The light pipe 300 may be hollow or solid and may have any cross sectional dimension shape including, but not limited to, rectangular, hexagonal, triangular, and the like. The shape of the light pipe 300 preferably matches the shape of the light source or LED 100 for high coupling efficiency.

The light pipe 300 may be uniform in cross-sectional dimension or may be tapered such that the cross-sectional dimension from the input end 310 to the output end 320 is increased or decreased. The optical recycling apparatus 200 including the light pipe 300 whose cross-sectional dimension increases can reduce the numerical aperture of the output. On the other hand, the optical recycling apparatus 200 including the light pipe 300 whose sectional dimension is reduced can improve the recycling of light at a large angle, thereby providing angular recycling of light.

The light pipe 300 may be made of glass, quartz, plastic, fused silica, acrylic, or the like. The light pipe 300 may have a bare surface or surface coated with a refractive index material that is similar to a standard optical fiber or the light pipe 300 may have a surface or portion entirely of aluminum and / Can be coated with the same refraction coating. Although the recycled light pipe 300 disclosed and illustrated herein is a solid light pipe, in actual commercial use, the light pipe 300 has an opening at the input end 310 and output end 320, a mirror As shown in FIG. The open ends of the input end 310 and the output end 320 are coated with an anti-reflective material to increase the efficiency of the light pipe 300 when recycling light.

A reflective medium 400 is mounted at the output end of the light pipe 300 to cover a portion of the output end 320 of the light pipe 300. The reflective medium 400 may be an external reflector, mirror, or reflective coating material. Alternatively, the reflective medium 400 may be incorporated into the light pipe 300, for example, by stacking the output terminal 320 of the light pipe 300 with a reflective coating. A portion of the light from the light source 100 is reflected back into the light pipe 300 because the reflective medium 400 covers a portion of the output end 320 of the light pipe 300. The reflected light 110 is transmitted to the light source 100 by the light pipe 300 and re-emitted or re-reflected into the light pipe 300 as an output from the light source 100, as shown in FIG. Since the area of the output end 320 of the light pipe 300 is reduced by the reflector 400, any light reflected back into the light pipe 300 by the reflector 400 is output from the light source 100 Thereby increasing or increasing the brightness of light present in the light pipe 300, thereby increasing the brightness of the illumination system according to an embodiment of the present invention. The total output power will be smaller from the light pipe 300 but the brightness of the light output will be increased by recycling a portion of the light from the light source 100 by the optical recycling apparatus 200 of the present invention.

Typically, the LED chip or die 100 has a certain reflectivity defined by the rate at which light is reflected at the surface relative to the amount of light incident on the surface. In addition, the surface of the LED chip 100 is non-specular and is defined by a scattering factor. The theoretical recycling efficiency of the space recycling apparatus 200 calculated by ray tracing for various LED reflectances is shown in FIG. The brightness enhancement of the space recycling apparatus 200 of the present invention is plotted against the number of LEDs, which is an inverse of the percentage (%) of the openings at the output end 320 of the light pipe 300. For example, the output of the space recycling apparatus 200 of the present invention is 1.9 times larger than the 60% LED reflectance for the 20% openings (corresponding to 5 LEDs) of the output end 320 of the light pipe 300 It is brighter.

Experimental results of a space recycling apparatus 200 using LEDs fabricated by vendors that are not disclosed are plotted against the theoretical curve in Fig. 24 and shown in Fig. The mirror 400 is disposed at the output end 320 of the light pipe 300 so that it can be adjusted to provide various percentages of openings. The coupling efficiency between the LED 100 and the light pipe 300 was not 100% since the LED chip 100 was mounted on the heat sink 140 together with the transparent window. Also, the reflectance of the mirror 400 at the output end 320 of the light pipe 300 was not 100%. Due to the reflectivity loss of the LED 100 and other experimental defects contributing to this loss, the observed reflections were less than the reflectance of the LEDs. The physical model of the experimental space recycling apparatus 200 was obtained by an ASAP ray tracing program with R (reflectance) and S (scattering) of the LED, which is a curve fitting parameter. In the best adjustment, it was found that the reflectance (R) was 52% and the scattering (S) was 18 degrees. In addition, the ASAP light projection was performed with the window removed so that the light pipe 300 was very close to the LED die 100. Figure 26 shows the calculation due to the LED die 100 in direct contact with the light pipe 300 with respect to the number of LEDs 100 which is an inverse of the percentage of the openings at the output end 320 of the light pipe 300 Lt; / RTI > For example, a 1.6-fold brightness enhancement may be applied to the LED die 100 using a space recycling device 200 that exists for a 20% opening (corresponding to 5 LEDs) of the output end 320 of the light pipe 300 / RTI >

4, the optical recycling apparatus 200 may include a polarizing beam splitter (PBS) 220 or a polarizer 210, preferably a reflective polarizer 210 , a reflective polarizer) to provide a polarization illumination system 1000. The reflective polarizer 210 or the PBS 220 may cover the entire output end 320 of the light pipe 300 or a portion of the output end 320 may not be covered by the reflector. The reflective polarizer 210 or the PBS 220 may also be disposed or mounted on the output end 320 of the light pipe 300 before and after the reflector 400. The reflective polarizer 210 or the PBS 220 reflects the undesired or unwantedly polarized light back to the light pipe 300 to improve the recycling efficiency of the optical recycling apparatus 200 of the present invention, .

According to an exemplary embodiment of the present invention, as shown in FIG. 4, the optical recycling apparatus 200 promotes scrambling of a light polarization state to increase the efficiency of the optical recycling apparatus 200 And a wave plate 230 (see FIG. The wave plate 230 may be disposed between the output end 320 of the light pipe 300 and the reflective polarizer 210.

5, the space and angle recycling apparatus 200 of the exemplary embodiment of the present invention includes an LED chip 100, a tapered light pipe 300 having an input end 310 narrower than the output end 320, Includes a mirror (400) around the periphery of the output end (320) of the tapered light pipe (300). The LED chip 100 is mounted on the heat sink 140. The narrow input end 310 of the tapered light pipe 300 is in optical communication with the LED chip 100. The air gap between the LED chip 100 and the input end 310 of the tapered light pipe 300 may be filled with a low index epoxy. By using the tapered light pipe 300 in this embodiment of the present invention, both the efficiency and the brightness within a specific cone angle are improved. When the LED 100 is used as a light source, brightness is usually the most important parameter because only light output within a small angle can be focused. For example, in a commercialized rear projection television (RPTV), the converging angle is estimated to be about 38 degrees, and light emitted from 38 to 90 degrees in this RPTV will not be used or discarded. The tapered recycled tapered light pipe 300 of the present invention collects light from the LED 100, selects an appropriate angle of light to be transmitted as an output, recycles the remaining light with the LED 100, And recycles unused light, effectively increasing the brightness of the LED 100. A mirror 400 disposed around the periphery of the output end 320 of the light pipe 300 reflects the light outside the selected angle to the LED 100 to recycle unused light. The amount of light output by the LED 100 using the space recycling apparatus 200 of the present invention within a selected angle is greater than the amount of light emitted by the LED 100 itself within a selected angle, Thereby increasing the brightness of the display panel 100.

According to an exemplary embodiment of the present invention, the (straight or tapered) recycling or regenerative light pipe 300 of the present invention can be incorporated with the packaging of the LED 100, as shown in Figs. 14A and 14B. The LED 100 and mounting frame 600 are mounted to a heat sink or substrate 140. A glass plate or lid 650 may be mounted on the mounting frame 600 and incorporated or attached to the light pipe 300. The glass cover 650 is also used to protect the LED chip 100. The size of the mounting frame 600 may be adjusted to control the gap 610 between the light pipe 300 and the LED chip 100. The light pipe 300 for light that is maximally coupled to the light pipe 300 and reflected back to the LED 100 through the light pipe 300 by the mirror 400 It is preferable that the LED chip 100 is closely located.

14A and 14B, a portion of the surface at the output end 320 of the light pipe 300 is covered with a reflective surface (e.g., reflective media, coating or mirror 400) Thereby promoting the recycling of light within the light source. The reflective medium 400 is preferably disposed around the periphery of the surface of the output end 320 of the light pipe 300. Although not shown, other configurations may be used, such as covering a portion of the output surface with a reflective medium 400 that is biased to one side or the other. As disclosed herein, the light pipe 300 may be attached to a glass cover 650 to facilitate mounting of various optical components of the optical recycling apparatus 200. The assembly process for the combined light pipe of the present invention is similar to standard LED assembly except that a glass cover 650 is formed with the light pipe 300. The light pipe 300 may be tapered, straight, solid or hollow depending on the application (to increase or decrease). The hollow light pipe can be assembled by attaching four mirrors to the cover glass 650 by means of epoxy, solder or other attachment means.

According to an exemplary embodiment of the present invention, a straight or tapered light pipe 300 can be combined with the packaging of multiple LED chips 100, such as the two LED chips 100 of Figs. 15A and 15B. Multiple LEDs or LED chips 100 are mounted on a heat sink or substrate 140 with a single mounting frame 600. 15A and 15B, the surface corresponding to the space between the LED chips 100 at the input end 310 of the light pipe 300 is a surface that enhances the recycling of light within the light pipe 300 Coated with a reflective coating.

Most LEDs have a lambertian emission pattern. A particular LED made of a photonic lattice has an enhanced emission pattern at a small angle so that the luminance is higher. In any case, the luminance at a small angle is higher than the luminance at a higher angle. As a result, if a higher luminance is required, only a small angle of light emission can be used, which discards all high angle light emission. This final system is very inefficient. In order to overcome this disadvantage, each recycling system is used so that each high emission is reflected back to the LED and only low emission is transmitted. Figure 5 shows a schematic of each recycling system.

Referring to Figures 6 to 8, 9B, 10B, 11B, 13C, 13D, 14B and 15B, the optical recycling apparatus 200 of the exemplary embodiment of the present invention includes a hollow or solid tapered light pipe (300). 6 shows an angle recycling apparatus 200 that includes a reduced tapered light pipe 300 tapered from a wider area to a smaller area (the input end 310 is greater than the output end 320). This reduced tapered light pipe 300 can be used to filter input light having a large incident angle. That is, the input light having a large incident angle is reflected and only the input light having a small incident angle will be transmitted by the reduced tapered light pipe 300. the input ray a0 entering the input end 310 of the reduced tapered light pipe 300 at an incident angle of? a is reflected by the inside of the reduced tapered light pipe 300 several times to be output as the output light a1 Escape through the output end 320 of the tapered light pipe 300. The input light can exit the increased tapered light pipe 300 at a larger incidence angle. the light beam b0 entering the input end 310 of the reduced tapered light pipe 300 is also reflected several times in the reduced tapered light pipe 300 but the reduced tapered light pipe 300 The incident angle of the light beam b0 exceeds 90 degrees before reaching the output end 320 of the light beam b0. Light beam b0 begins to be reflected back towards the input end 310 of the reduced tapered light pipe 300 to form a reduced beam b1 as shown in Figure 6, But exits the input end 310 rather than the input end 320. The reduced tapered light pipe 300 acts as each filter for the incident input light, in which light of a small incident angle is transmitted and light of a large incident angle is rejected or reflected by the reduced tapered light pipe 300.

As shown in FIGS. 7, 8, 9B, 10B, 11B, 13C, 13D, 14B and 15B, the angle recycling apparatus 200 of the exemplary embodiment of the present invention includes a reduced tapered light Includes a pipe (300) and a plurality of LEDs (100). The LED 100 is disposed in front of the input end 310 of the reduced tapered light pipe 300 where the area of the LED 100 is reduced to the area of the input end 310 of the reduced tapered light pipe 300 and It is largely the same. Light of a high incidence angle or light of a high angle is reflected back to the LED 100 by the reduced tapered light pipe 300 of the present invention. The reflected light is recycled in the LED 100 and reflected back into the reduced tapered light pipe 300 with a different angular distribution than the original input light. That is, a portion of the recycled and reflected light has a small incident angle (or small angular light) to be transmitted by the reduced tapered light pipe 300 and coupled to the output of the reduced tapered light pipe 300. Light at a small angle exits the output end 320 of the reduced tapered light pipe 300 as an output. Because the LED surface has scattering, a portion of the light reflected at a high angle is scattered at a low angle and coupled out of the angle recycling device 200 to increase the brightness of the illumination system 1000. 8, the output end 320 of the reduced tapered light pipe 300 of the exemplary embodiment of the present invention is connected to the input (not shown) of another tapered light pipe 300 (preferably an increased tapered light pipe) May be coupled to end 310 to reduce high angle light from the LED, but increase the light output area.

According to an exemplary embodiment of the present invention, illumination system 1000 includes a plurality of LEDs 100 coupled to a single output light pipe 300. 11A, 11B and 12, two LEDs 100 according to an exemplary embodiment of the present invention include two tapered input light pipes 350, preferably an increased tapered light pipe 350, To a single output light pipe 300 (either a straight light pipe as in FIG. 11 or a tapered light pipe as in FIG. 11B). The hysteresis end of the tapered input light pipe 350 is individually coupled to the two LEDs 100 and the output end of the tapered input light pipe 350 is coupled to the output light pipe 300. As described herein, the output end 320 of the output light pipe 300 is partially coated with a reflective coating or medium to promote recycling within the optical recycling apparatus 200 so that the brightness of the illumination system 1000 . The dimensions of the output ends of the tapered input light pipe 350 are determined by the dimensions of the input end of the output light pipe 300 and the dimensions of the input end of the output light pipe 350. [ It is preferable to match them.

As shown in Figures 9A, 9B, 10A, 10B, 11A, 11B, and 12, the illumination system 1000 of an exemplary embodiment of the present invention includes a plurality of LED chips or LEDs 100, (E.g., columns of LEDs) or a two-dimensional array. As shown in FIGS. 11A, 11B, and 12, the LED / LED chip 100 and the input light pipe 350 are preferably packed closely or closely. The shapes of the LED 100 and the input light pipe 350 may be circular, triangular, hexagonal, octagonal, or the like. The dimensions of LED 100 and input light pipe 350 may be uniform, but may vary depending on the application of the illumination system. That is, the optical recycling apparatus 200 may include a plurality of input light pipes 350 having various shapes and dimensions, and a plurality of LEDs 100 having various shapes and dimensions. According to an exemplary embodiment, the LED 100 and the input light pipe 350 to which the LED 100 is coupled have a generally similar shape. For example, the triangular input light pipe 350 is coupled to the triangular LED 100. As such, the illumination system 1000 of the present invention is advantageous in that it is designed to provide a specific output power by combining conventional readily available LEDs of varying output power and size. Additionally, multiple LEDs 100 are used to further provide an averaging effect on output power and wavelength. Typically, the output power and wavelength of an LED / LED chip in an LED product is not well controlled. Current LED products need to "bin " the LED chips with several wavelengths and several power ranges. If several LEDs are combined into a single output source in accordance with various embodiments of the present invention, the average variation of the illumination system 1000 (or light source) will be less overall at both the output power and wavelength. If enough LEDs are used as a single light output source as in the various embodiments of the present application, the above bundles are not needed, thereby improving the yield of the LED / LED chips and reducing the manufacturing cost.

Typically two or more colors are used in the color projection system. In accordance with an exemplary embodiment of the present invention, illumination system 1000 is described, for example, in U.S. Patent Nos. 5,054,502, Multiple Light Sources "filed 11 / 351,013, which are incorporated herein by reference in their entirety. That is, for example, the present invention can be used to provide three-color (red, green and blue) projection systems or four-color and five-color projection systems that start up to obtain some momentum.

9A, 9B, 10A, and 10B, the optical recycling apparatus 200 of the exemplary embodiment of the present invention includes multiple LED chips coupled to the input end 310 of the light pipe 300 . As disclosed herein, the LED chip 100 is packaged densely with minimal space between the LED chips 100. The space between the LED chips 100 may be reflective, partially reflective or non-reflective, but preferably such space is reflective to enhance light recycling, thereby increasing the efficiency of the optical recycling apparatus 200. 9A and 9B, the surface (i.e., the space 130) of the substrate 140 between the LED chips 100 of the exemplary embodiment of the present invention is reflected (or refracted) using a reflector, a mirror, . Alternatively, as shown in FIGS. 10A and 10B, the input end 310 of the light pipe 300 corresponding to the space 130 between the LED chips 100 may be reflective (e.g., reflective) using mirrors, . Although only the incremental tapered light pipe 300 is shown in Figures 9b and 10b, the tapered light pipe 300 or reduction (large input end for the small output end) tapered light pipe 300 (small input end for the large output end) Any one of the light pipes 300 may be used. Incremental tapered light pipe 300 can be used to reduce the output numerical aperture and reduced tapered light pipe 300 can be used to improve recycling of light with a high incident angle.

13A and 13B, the illumination system 1000 of an exemplary embodiment of the present invention includes a light pipe 300 (either a straight or tapered light pipe) or a variety of color LEDs 100 And a color beam combiner 700 for combining the output from each LED 100 (which emits light having wavelengths) into a single output 250. 13A, the color beam combiner 700 includes cube prisms P1, P2, and P3 (preferably, cube prisms P1, P2, and P3) for combining outputs from various color LEDs 100, such as red, Polarized beam splitter) and cubes G1 and G2. The cube prism P3 is coupled to the input end 310 of the light pipe 300. The red LED (R-LED) 100 emits red light reflected by the cube G1 by the cube prism P1. The cube prism P2 transmits the red light received from the cube G1 and reflects the green light emitted by the green LED (G-LED) The cube prism P2 transmits both the reflected green light and the transmitted red light to the cube G2. The cube prism P3 transmits both the green light and the red light received from the cube G2 and reflects the blue light emitted by the blue LED (B-LED) 100 to the light pipe 300. [ All sides of the cube prism 710, the cube 720 and the light pipe 300 are preferably polished for efficient guidance through the various optical components of the illumination system 1000. The output end 320 of the light pipe 300 may have a reflective coating, reflector, or mirror 400 that covers a portion of the output end 320 to enhance recycling, Thereby increasing the brightness.

Alternatively, the color beam combiner 700, such as the triangular prism 730, and the light pipe 300 are integrated together. 13B, illumination system 1000 includes R-LED 100, G-LED 100 and B-LED 100, waveguide sections W1-W5 and output section 300 Or may be a straight line). The waveguide sections W1, W3 and W5 are preferably triangular prisms. The red LED (R-LED) 100 emits red light reflected by the waveguide section W1 to the waveguide section W2. The waveguide section W3 transmits the received red light from the waveguide section W2 and reflects the green light emitted by the green LED (G-LED) 100. The waveguide section W3 transmits both the reflected green light and the transmitted red light to the waveguide section W4. The waveguide section W5 transmits both the received green and red light from the waveguide section W4 and reflects the blue light emitted by the blue LED (B-LED) 100 to the output section 300. One example of a color beam combiner is disclosed in co-pending application Serial No. 11 / 351,013, which is incorporated herein by reference in its entirety. All sides of the waveguide sections W1-W5 and the output section 300 are preferably polished for efficient guidance through the various optical components of the illumination system 1000. The output end 320 of the output section 300 may have a reflective coating, reflector, or mirror 400 covering a portion of the output end to enhance recycling, thereby reducing the brightness of the illumination system 1000 .

According to an exemplary embodiment of the present invention, the illumination system 1000 includes an angle recycling apparatus 200. 16, the angle recycling apparatus 200 includes an LED 100 mounted on a heat sink 140, a plastic or glass (not shown) having reflective concave surfaces 820, 830 and a lens surface 810 800). ≪ / RTI > The reflective concave surfaces 820 and 830 preferably surround the lens surface 810. The shape of the reflective concave surfaces 820, 830 can be spherical, parabolic, or elliptical, and can be reflective by a reflective coating. Reflective surfaces 820 and 830 operate as retro-reflectors that retroreflect each high ray into LED 100 for recycling. Each small ray from the LED 100 is coupled by the lens surface 810 and output from the angle recycling device 200 as an output 250.

17, the angle recycling apparatus 200 includes an LED 100 mounted on a heat sink 140, reflectors 840 and 850, and a lens 860. [ A high angle of light from LED 100 is reflected back to the LED by reflectors 840 and 850 for recycling and a small angle of light from LED 100 is coupled by lens 860 to produce output 250 And is output from the angle recycling apparatus 200 as an angle.

As shown in FIG. 18, the angled recycling apparatus 200 of FIGS. 16 and 17 of the exemplary embodiment of the present invention includes a dual parabolic reflector 840, 850, or the reflective surfaces 820, Lt; RTI ID = 0.0 > reflections < / RTI & That is, the light reflected from the reflective surface 820 or the reflector 840 is collimated and received by the reflective surface 830 or the reflector 850, respectively. The collimated light is then re-focused by the reflective surface 830 or reflector 850 for recycling and is focused onto the LED 100. The radius of curvature of the reflective surfaces 820 and 830 and the reflectors 840 and 850 may also be such that the reflective surfaces 820 and 830 or the reflectors 840 and 850 are closer to the LED than the lens surface 810 or lens 860. [ The radius of curvature of the lens surface 810 or the lens 860 may be smaller than the radius of curvature of the lens surface 810 or the lens 860.

According to an exemplary embodiment of the present invention, the optical recycling apparatus 200 of the present invention can be incorporated into a conventional LED lighting system to increase the brightness of an LED source using space and / or each recycling of light. Typically, in a conventional LED illumination system, light from the LED chip 100 is coupled to an application 900 (e.g., a projection display screen) via an external optical system 800. 19, the space and / or each optical recycling apparatus 200 of the present invention is inserted between the LED chip 100 and the external optical system 800 to increase the brightness of the light in the application 900. [

20, the spatial and / or angular recycling apparatus 200 of the present invention may be combined with an integrated optical device 850, such as a molded lens on an LED package, to extract light from the LED chip 100 Can be incorporated into a conventional LED lighting system having an LED chip (100). At this time, the spatial and / or angular recycling apparatus 200 of the present invention is inserted between the integrated optical apparatus 850 and the external optical system 800 to improve the brightness of the light in the application 900.

In accordance with an exemplary embodiment of the present invention, the optical recycling apparatus 200 of the present invention increases the amount of light coupled to the projection system 950 and / or the brightness of the LEDs using space and / or respective recycling of light To a conventional LED projection system. In a conventional LED projection system, light from the LED chip 100 is typically coupled to the projection system 950 using a lens or lens system 810. 21, the space and / or each optical recycling apparatus 200 of the present invention may be inserted between the LED chip 100 and the lens 810 to control the amount of light coupled to the projection system 950 and / / RTI > and / or increases the brightness of the light.

22, the inventive spatial and / or angular recycling apparatus 200 of the exemplary embodiment of the present invention can be incorporated into a fiber optics system and can be integrated into an optical fiber 920 to provide a total optical And the brightness of the LED source. At this time, the space and / or angle recycling apparatus 200 of the present invention is inserted between the LED chip 100 and the lens 810 to increase the amount of light coupled to the optical fiber 920 and / or the brightness of the light.

23, the space and / or angle recycling apparatus 200 of the present invention can be used in the LED projection system of FIG. 21, or in an integrated optical device for extracting light from the LED chip 100 850, which may be incorporated into the optical fiber system of FIG. The spatial and / or angular recycling apparatus 200 of the present invention may be used to control the amount of light inserted into the optical fiber 920 or the projection system 950 inserted between the integrated optics 850 and the lens 810, / RTI > and / or increases the brightness of the light.

It will be understood by those skilled in the art that the invention disclosed herein may be varied in many ways within the spirit and scope of the invention. Any and all such modifications are intended to be included within the scope of the following claims.

Claims (53)

An illumination device for increasing the brightness of a light source, A light source for emitting a plurality of light beams, And an optical recycling device coupled to the light source for transmitting the plurality of light beams from the light source and for recycling some light rays outside a selected one of the plurality of light beams to the light source, Wherein the light source causes the optical recycling apparatus to re-emit the partial light beam among the plurality of light beams to increase the luminance of the output of the light source, Wherein the optical recycling apparatus comprises an angular recycling device including an input end for receiving the plurality of light beams from the light source and a solid optical element in the form of a reduced tapered light pipe having an output end, Wherein the reflective surface of the solid optical element reflects all of the light rays outside the selected angle incident on the reflective surface for recycling to the light source, Wherein the lens surface of the solid optical element is configured to partially overlap a portion of the output end of the light pipe that is not covered by the reflective surface, . delete delete The lighting device according to claim 1, wherein the light pipe is an optical fiber. The lighting device according to claim 1, wherein the light pipe has one of a circular shape, a triangular shape, a hexagonal shape, or an octagonal shape. The lighting apparatus according to claim 1, wherein the light pipe comprises one of glass, quartz or plastic. 2. The lighting apparatus according to claim 1, wherein the surface of the light pipe is coated with a reflective coating material or a material having a refractive index for guiding light, and the input end of the light pipe is coated with an anti-reflective coating. 6. The lighting apparatus according to claim 5, wherein the inner wall of the light pipe is coated with a reflective coating. The optical recycling apparatus of claim 1, wherein the optical recycling apparatus further comprises a reflective polarizer or a polarizing beam splitter covering the output end of the light pipe, wherein some of the plurality of light beams are reflected by the reflective polarizer or the reflective beam splitter Recycled lighting devices. 10. The illumination system of claim 9, wherein the optical recycling apparatus comprises a wave plate for promoting scrambling of the polarization states of the plurality of light beams. delete delete The light pipe of claim 1, wherein the reflective surface comprises a reflector, mirror or reflective coating that covers a portion of the output end of the light pipe, the reflector, mirror, or reflective coating covering the periphery of the output end of the light pipe And reflects the part of the plurality of light beams back to the light source, thereby providing both space recycling and angle recycling of light. The lighting device of claim 1, wherein the light source comprises a light emitting diode (LED) or an LED chip, the dimension of the input end of the light pipe being equal to the dimension of the LED. 15. The lighting apparatus according to claim 14, wherein the optical recycling apparatus includes an air gap between the input end of the light pipe and the LED chip. 16. The lighting apparatus of claim 15, wherein the air gap is filled with epoxy having a refractive index for optical communication between the LED chip and the input end of the light pipe. 15. The lighting device of claim 14, wherein the LED chip is mounted on a substrate having a reflective coating. The optical recycling apparatus according to claim 17, wherein the optical recycling apparatus includes a mounting frame mounted on the substrate, and a glass plate attached to the light pipe and mounted on the mounting frame, A lighting device that can be adjusted to control air gaps between LED chips. 19. The light pipe of claim 18, wherein the light source comprises a plurality of LED chips coupled to the light pipe, and a space between the plurality of LED chips on the substrate further comprises a reflective coating portion to promote recycling of light in the light pipe . 19. The light pipe of claim 18, wherein the light source comprises a plurality of LED chips coupled to the light pipe, wherein a space between the plurality of LED chips in front of the input end of the light pipe causes recycling of light in the light pipe And a reflective coating portion for enhancing the brightness of the light. 2. The LED package of claim 1, wherein the light source comprises a plurality of LED chips, the plurality of LED chips being each coupled to an input end of an incremental tapered light pipe to provide a pair of LED light pipes, And an output end of the pipe is coupled to the input end of the light pipe. 22. The lighting apparatus of claim 21, wherein the plurality of LED chips are densely packaged in a single dimensional or two-dimensional array, and the cross-sectional dimensions of the pair of LED light pipes are the same. The illumination apparatus according to claim 1, wherein the optical recycling apparatus comprises: a plurality of color LED chips emitting light of different wavelengths; and a color beam combiner coupling the plurality of light beams from the plurality of color LED chips. The optical recycling apparatus according to claim 1, wherein the optical recycling apparatus is an angle recycling apparatus including a reduced tapered light pipe, Wherein the reduced tapered light pipe has a cross sectional dimension of the input end greater than the output end of the reduced tapered light pipe and the angle recycling device reflects the light outside the selected angle back to the light source, To said output end of said light pipe, thereby recycling said part of said plurality of light rays angularly. 26. The method of claim 24, wherein the reflective surface comprises a reflector, mirror, or reflective coating that covers a portion of the output end of the reduced tapered light pipe to reflect the portion of the plurality of light rays back to the light source, And a light source for spatially recycling the part of the plurality of light beams. 26. The apparatus of claim 24, wherein the angle recycling apparatus includes an incremental tapered light pipe coupled to an output end of the reduced tapered light pipe, wherein the selected angle of light from the light source And the light rays outside are reduced. delete 2. The illumination system of claim 1, wherein the reflective surface forms a dual parabolic reflective surface that reflects light rays outside the selected angle twice before the light rays outside the selected angle are refocused onto the light source. The optical recycling apparatus according to claim 1, wherein the optical recycling apparatus includes: a reflector for reflecting the light ray outside the selected angle back to the light source and recycling the part of the plurality of light rays angularly; And a lens for transmitting the light to the output end of the pipe. 30. The illumination apparatus of claim 29, wherein the reflector forms a dual parabolic reflector that reflects a ray of light outside the selected angle twice before the ray outside the selected angle is refocused onto the light source. 2. The apparatus of claim 1, wherein when the illumination device is used in an LED projection system, the light source is an LED chip, the optical recycling device is disposed between the LED chip and the lens system, A system disposed between the system and for increasing the amount of light coupled to the LED projection system. 32. The lighting device of claim 31, wherein the LED chip comprises a coalescing optic for extracting light from the LED chip. 2. The optical recycling apparatus according to claim 1, wherein when the illumination device is used in an optical fiber system, the light source is an LED chip, the optical recycling device is disposed between the LED chip and the lens system and the lens system is disposed between the optical fiber system and the optical recycling device To increase the amount of light coupled to the optical fiber system. 34. The lighting apparatus of claim 33, wherein the LED chip comprises a coalescing optic for extracting light from the LED chip. A method for increasing the brightness of a light source, Coupling an optical recycling apparatus to a light source to receive a plurality of light beams from the light source; Recycling a portion of the plurality of light rays outside the selected angle to the light source; A step of re-emitting the partial light beam among the plurality of light beams to the optical recycling apparatus by the light source, the method comprising a re-light emitting step of increasing the luminance of the output of the light source, Wherein the optical recycling apparatus comprises an angular recycling device including an input end for receiving the plurality of light beams from the light source and a solid optical element in the form of a reduced tapered light pipe having an output end, Wherein the reflective surface of the solid optical element reflects all of the light rays outside the selected angle incident on the reflective surface for recycling to the light source, Wherein the lens surface of the solid optical element is configured to partially overlap a portion of the output end of the light pipe that is not covered by the reflective surface, To increase the brightness. delete 36. The optical recycling apparatus of claim 35, wherein the optical recycling apparatus further comprises a reflective polarizer or a polarizing beam splitter covering the output end of the light pipe, and the recycling step includes applying a portion of the plurality of light beams to the reflective polarizer or the reflective beam splitter And reflecting the light reflected by the light source. 38. The method of claim 37, further comprising scrambling the polarization states of the plurality of light beams. delete 37. The method of claim 35, wherein the recycling step includes reflecting some of the plurality of light rays outside the selected angle back to the light source, thereby providing both space recycling and angle recycling of light. 36. The method of claim 35, wherein the light source comprises an LED chip or LED chip having the same cross-sectional dimension as the input end of the optical recycling apparatus. 42. The method of claim 41, further comprising the step of filling the air gap between the LED chip and the input end of the optical recycling apparatus with an epoxy of refractive index for optical communication between the LED chip and the input end . 42. The method of claim 41, further comprising mounting the LED chip on a substrate having a reflective coating. 44. The method of claim 43, further comprising the steps of: mounting a mounting frame, a glass plate attached to the light pipe on the substrate, and adjusting the size of the mounting frame so that the distance between the input end of the optical recycling apparatus and the LED chip Further comprising the step of controlling an air gap. 45. The method of claim 44, further comprising: mounting a plurality of LED chips, each coupled to the input end of the optical recycling apparatus, Further comprising: reflectively coating a space between the plurality of LED chips on the substrate to promote light recycling in the optical recycling apparatus. 45. The method of claim 44, further comprising: mounting a plurality of LED chips, each coupled to the input end of the optical recycling apparatus, Further comprising reflectively coating a space between the plurality of LED chips in front of the input end of the optical recycling device to promote light recycling in the optical recycling device. 42. The method of claim 41, further comprising mounting a plurality of LED chips densely packaged in a single dimensional or two-dimensional array on a substrate. 37. The light emitting diode of claim 35, wherein the light source is a plurality of color LED chips, Receiving the plurality of light beams having different wavelengths from a plurality of color LED chips, And combining the plurality of light beams from the plurality of color LED chips. 36. The method of claim 35, wherein the coupling step comprises coupling an angle recycling device including a reduced tapered light pipe having a cross sectional dimension of the input end greater than a cross sectional dimension of the output end, Wherein the recycling step includes retracting the light rays outside the selected angle to the light source through the input end of the reduced tapered light pipe and transmitting the light rays within the selected angle to the output end of the reduced tapered light pipe, And recycling the part of the light rays of the second light source in an angular manner. 50. The method of claim 49, wherein the reflective surface comprises a reflector, mirror, or reflective coating that covers a portion of the output end of the reduced tapered light pipe, and wherein the recycling is performed using the reflector, mirror, Spatially recycling the portion of the plurality of light rays by reflecting the portion of the light rays of the plurality of light rays back to the light source, Increase method. 50. The method of claim 49, further comprising coupling an increasing tapered light pipe to the output end of the reduced tapered light pipe to increase the light output area of the light source, Of the light beam. delete delete

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